With the development of the computer technology, people are enjoying working and entertainment through various files. The files people are using might have been downloaded from the internet, or have been obtained through portable storage medium, or might have been received through interconnection with other people. Accordingly, from the aspect of the users, high possibility lies that the files obtained through various ways, as well as within the terminal devices such as computers and mobile phones could be suspicious. Moreover, great harm would be caused to the files people are using through the overflow of the virus program or Trojans contained in the suspicious files.
However, only the scanning engines of the local clients and the local virus library are used in scanning the suspicious files. The client engines are anti-virus engines while the virus signature database with the local virus library is limited, as comparing to the fact that the number of virus features and Trojans are growing rapidly far more than the updating speed of the local virus library, thereby the local virus library could only improve the updating frequency very passively.
Due to the incompetency that the virus signature database of the local virus library could not cover all the virus features and Trojans, low efficiency lies when using the client engine to scan suspicious files.